001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017 package org.apache.logging.log4j.core.appender;
018
019 import java.io.IOException;
020 import java.io.OutputStream;
021
022 import org.apache.logging.log4j.core.Layout;
023
024 /**
025 * Manages an OutputStream so that it can be shared by multiple Appenders and will
026 * allow appenders to reconfigure without requiring a new stream.
027 */
028 public class OutputStreamManager extends AbstractManager {
029
030 private volatile OutputStream os;
031 protected final Layout<?> layout;
032
033 protected OutputStreamManager(final OutputStream os, final String streamName, final Layout<?> layout) {
034 super(streamName);
035 this.os = os;
036 this.layout = layout;
037 if (layout != null) {
038 final byte[] header = layout.getHeader();
039 if (header != null) {
040 try {
041 this.os.write(header, 0, header.length);
042 } catch (final IOException ioe) {
043 LOGGER.error("Unable to write header", ioe);
044 }
045 }
046 }
047 }
048
049 /**
050 * Creates a Manager.
051 *
052 * @param name The name of the stream to manage.
053 * @param data The data to pass to the Manager.
054 * @param factory The factory to use to create the Manager.
055 * @param <T> The type of the OutputStreamManager.
056 * @return An OutputStreamManager.
057 */
058 public static <T> OutputStreamManager getManager(final String name, final T data,
059 final ManagerFactory<? extends OutputStreamManager, T> factory) {
060 return AbstractManager.getManager(name, factory, data);
061 }
062
063 /**
064 * Default hook to write footer during close.
065 */
066 @Override
067 public void releaseSub() {
068 writeFooter();
069 close();
070 }
071
072 /**
073 * Writes the footer.
074 */
075 protected void writeFooter() {
076 if (layout == null) {
077 return;
078 }
079 final byte[] footer = layout.getFooter();
080 if (footer != null) {
081 write(footer);
082 }
083 }
084
085 /**
086 * Returns the status of the stream.
087 * @return true if the stream is open, false if it is not.
088 */
089 public boolean isOpen() {
090 return getCount() > 0;
091 }
092
093 protected OutputStream getOutputStream() {
094 return os;
095 }
096
097 protected void setOutputStream(final OutputStream os) {
098 final byte[] header = layout.getHeader();
099 if (header != null) {
100 try {
101 os.write(header, 0, header.length);
102 this.os = os; // only update field if os.write() succeeded
103 } catch (final IOException ioe) {
104 LOGGER.error("Unable to write header", ioe);
105 }
106 } else {
107 this.os = os;
108 }
109 }
110
111 /**
112 * Some output streams synchronize writes while others do not. Synchronizing here insures that
113 * log events won't be intertwined.
114 * @param bytes The serialized Log event.
115 * @param offset The offset into the byte array.
116 * @param length The number of bytes to write.
117 * @throws AppenderLoggingException if an error occurs.
118 */
119 protected synchronized void write(final byte[] bytes, final int offset, final int length) {
120 //System.out.println("write " + count);
121 try {
122 os.write(bytes, offset, length);
123 } catch (final IOException ex) {
124 final String msg = "Error writing to stream " + getName();
125 throw new AppenderLoggingException(msg, ex);
126 }
127 }
128
129 /**
130 * Some output streams synchronize writes while others do not.
131 * @param bytes The serialized Log event.
132 * @throws AppenderLoggingException if an error occurs.
133 */
134 protected void write(final byte[] bytes) {
135 write(bytes, 0, bytes.length);
136 }
137
138 protected synchronized void close() {
139 final OutputStream stream = os; // access volatile field only once per method
140 if (stream == System.out || stream == System.err) {
141 return;
142 }
143 try {
144 stream.close();
145 } catch (final IOException ex) {
146 LOGGER.error("Unable to close stream " + getName() + ". " + ex);
147 }
148 }
149
150 /**
151 * Flushes any buffers.
152 */
153 public synchronized void flush() {
154 try {
155 os.flush();
156 } catch (final IOException ex) {
157 final String msg = "Error flushing stream " + getName();
158 throw new AppenderLoggingException(msg, ex);
159 }
160 }
161 }